Year	Percent (Units)
1990	0.627
1991	0.608
1992	0.559
1993	0.557
1994	0.543
1995	0.533
1996	0.534
1997	0.528
1998	0.527
1999	0.512
2000	0.515
2001	0.537
2002	0.598
2003	0.630
2004	0.660
2005	0.675
2006	0.684
2007	0.698
2008	0.727
2009	0.791
2010	0.836
2011	0.844
2012	0.828
2013	0.847
2014	0.884
2015	0.876
2016	0.836
2017	0.807
2018	0.795
2019	0.790
2020	0.799
2021	0.779
2022	0.778
2023	0.776
2024	0.778
2025	0.776
2026	0.775
2027	0.776
2028	0.778
2029	0.780